1. Field of the Invention
The present invention pertains to the art of dishwashers and, more particularly, to a dishwasher tub body formed from a multi-layer composite structure.
2. Discussion of the Prior Art
A typical dishwasher includes a tub having a front opening that leads to an interior washing compartment and a door that pivotally mounts, in a sealable manner, across the front opening. Dishwasher tubs are typically formed from reinforced molded plastic having an inner surface provided with a finish that is resistant to food stains. However, through exposure to certain foods over time, the inner surface can become discolored. In higher end dishwasher models, the tub is formed from stamped and welded stainless steel which is more impervious to stains.
Stamped and welded stainless steel tubs currently employed in the dishwasher industry are formed from a fairly heavy gauge (0.22-0.26 inches; 5.59-6.60 mm) stainless steel material. The stainless steel material is stamped into shape using very expensive metal stamping equipment. The tub is formed in two parts which then must be both welded and crimped to achieve a water tight enclosure. The stamping machinery includes a specific mold that forms a particular tub half with each operation. Stamping, welding and crimping the components, coupled with the need to change stamping molds for each dishwasher model, is a costly and time consuming process.
In addition to serving as the washing compartment stainless steel tubs provide structural support for the dishwasher, thus the requirement for the heavy gauge stainless steel. However, stainless steel tubs must also be provided with support ribs and an exterior coating of a mastic material which acts both as a sound deadening and insulation layer. The need for heavy gauge steel, ribs and the requirement of the mastic layer further increases costs associated with the manufacturing process.
In connection with the present invention, a need has been recognized for a stain resistant dishwasher tub that is both easy to manufacture and modular. The tub would also provide any necessary sound/thermal insulation and structural support for the appliance.